Boron nitride and boron nitride-derived materials deposition method

ABSTRACT

Methods for forming boron-containing films are provided. The methods include introducing a boron-containing precursor and a nitrogen or oxygen-containing precursor into a chamber and forming a boron nitride or boron oxide film on a substrate in the chamber. In one aspect, the method includes depositing a boron-containing film and then exposing the boron-containing film to the nitrogen-containing or oxygen-containing precursor to incorporate nitrogen or oxygen into the film. The deposition of the boron-containing film and exposure of the film to the precursor may be performed for multiple cycles to obtain a desired thickness of the film. In another aspect, the method includes reacting the boron-containing precursor and the nitrogen-containing or oxygen-containing precursor to chemically vapor deposit the boron nitride or boron oxide film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 60/939,802, filed May 23, 2007, which is herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to methods offorming films on substrates, such as semiconductor substrates. Moreparticularly, embodiments of the present invention relate to methods forforming boron nitride films on substrates.

2. Description of the Related Art

Integrated circuit geometries have dramatically decreased in size sincesuch devices were first introduced several decades ago. Since then,integrated circuits have generally followed the two year/half-size rule(often called Moore's Law), which means that the number of devices on achip doubles every two years. Today's fabrication facilities areroutinely producing devices having 0.13 μm and even 0.1 μm featuresizes, and tomorrow's facilities soon will be producing devices havingeven smaller feature sizes.

The continued reduction in device geometries has generated a demand fordielectric films having lower dielectric constant (k) values because thecapacitive coupling between adjacent metal lines must be reduced tofurther reduce the size of devices on integrated circuits.

The continued reduction in device geometries and the increasingly densespacing of devices on semiconductor substrates have also presentedchallenges in the area of improving device performance. For example,while the performance of a metal-oxide-semiconductor field effecttransistor (MOSFET) device can be improved by several methods, such asreducing the gate dielectric thickness of the device, the very thindielectric layers required by small devices may allow dopants from thegate electrode to penetrate through the gate dielectric into theunderlying silicon substrate. A very thin gate dielectric may alsoincrease gate leakage that increases the amount of power consumed by thegate and eventually damages the transistor.

Straining the atomic lattice of materials in devices is a recentlydeveloped, alternative method of improving device performance. Strainingthe atomic lattice improves device performance by increasing carriermobility in a semiconductor material. The atomic lattice of one layer ofa device can be strained by depositing a stressed film over the layer.For example, stressed silicon nitride layers used as etch stop layersover a gate electrode can be deposited to induce strain in the channelregion of the transistor. The stressed silicon nitride layers can havecompressive stress or tensile stress.

While plasma-enhanced chemical vapor deposited (PECVD) silicon nitride(SiN) layers having relatively high stress levels have been developed,there remains a need for a method for forming dielectric layers thathave higher compressive or tensile stress levels and a lower dielectricconstant (k) than SiN layers, which typically have a dielectric constantof about 7.

SUMMARY OF THE INVENTION

Embodiments of the present invention generally provide methods offorming boron-containing films, such as boron nitride films and boronoxide films. In one embodiment, a method of forming a boron nitride filmor a boron oxide film comprises introducing a boron-containing precursorinto a chamber and depositing a boron-containing film on a substrate inthe chamber from the boron-containing precursor. The boron-containingfilm is treated to increase the nitrogen or oxygen content in the filmand form a boron nitride film or boron oxide film. Treating theboron-containing film comprises exposing the boron-containing film to anitrogen-containing precursor or an oxygen-containing precursor.Treating the boron-containing film may also comprise a plasma process, aUV cure process, a thermal anneal process, or a combination thereof. Theintroducing, depositing, and treating are repeated until a desiredthickness of the boron nitride film or boron oxide film is obtained.

In another embodiment, a method of forming a boron nitride film or aboron oxide film comprises introducing a boron-containing precursor anda nitrogen-containing precursor or an oxygen-containing precursor into achamber. The boron-containing precursor and the nitrogen-containingprecursor or the oxygen-containing precursor are reacted to chemicallyvapor deposit a boron nitride film or boron oxide film on a substrate inthe chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a flow chart of an embodiment of a method of forming a boronnitride or boron oxide film.

FIG. 2 is a FTIR that shows the effect of different N₂ flow rates duringtreatment of boron-containing films with N₂ on the composition ofresulting boron nitride layers according to embodiments of theinvention.

FIG. 3 is a FTIR that shows the effect of different substrate supporttemperatures during the deposition of boron-containing films on thecomposition of the subsequently formed boron nitride layers according toembodiments of the invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide methods of depositing boronnitride, boron oxide and boron carbide films. The boron nitride, oxideand carbide films may be undoped boron nitride (BN), undoped boron oxide(B₂O₃) and undoped boron carbide (BC) films, or doped boron nitride,boron oxide or boron carbide films, such as boron silicon nitride(BSiN), boron silicon oxide (BSixOy), boron carbon nitride (BCN),phosphorus boron nitride (PBN), silicon boron nitride (SiBN) and boroncarbon silicon nitride (BCSiN) films.

The boron nitride, boron carbide and boron oxide films may be used forfront end applications, such as spacer layers and strain-inducinglayers, i.e., a stress nitride layer, which is deposited to control thestress of an underlying film. The boron nitride films may have adielectric constant between 1.1 and 10. For example, boron nitride filmshaving a dielectric constant between 1.1 and 6.0 may be deposited by adeposition method comprising introducing the film precursors into achamber simultaneously. The boron nitride films may be stress nitridelayers having a stress between 10 GPa compressive and 10 GPa tensile,such as a tensile stress that is greater than about 2.0 GPa or acompressive stress that is less than about −3.5 GPa. The boron nitridefilms have a high step coverage and low pattern loading effect. Asdefined herein, films with a high step coverage have a lower percentageof film thickness difference between different surfaces of a feature,i.e., sidewalls, top, and bottom, than films with low step coverage. Thepattern loading effect (PLE) is defined as the percentage of filmthickness difference between a film thickness on portion, such as thebottom, top, or sidewall, of a feature in a substrate region with a fewfeatures (an isolated area) and a film thickness on a correspondingportion of a feature in a substrate region with high density of features(a dense area), and thus, a lower pattern loading effect percentagereflects a higher film thickness uniformity across a substrate.

The boron-containing films may also be used as a boron source layers fordoping an underlying layer with boron. For example, a boron nitride filmmay be deposited on a silicon layer and then annealed in order tointroduce boron into the silicon layer to form a shallow junction in thesilicon layer. The boron nitride film may be removed after a desiredamount of boron is introduced into the silicon layer.

Additional embodiments provide methods comprising depositing a boronnitride or boron oxide liner on a substrate before or after aboron-containing film is deposited on the substrate. Theboron-containing film can be a high stress, boron-rich film. Thedeposition of the boron nitride or boron oxide liner on top of and/orunderneath the boron-rich film prevents boron out-diffusion from theboron-rich film and reduces the leakage current through the boron-richfilm. If the boron-rich film is used as a boron-diffusion source, theliner is deposited on the side of the film where the boron diffusion isnot desired. For example, the liner may be deposited underneath aboron-rich film that is intended to dope a SiO₂ film deposited on top ofthe boron-rich film. In another example, the liner may be deposited ontop of a boron-rich film that is used as a dopant source for thesubstrate (i.e., Si) underneath the boron-rich film.

The boron nitride or oxide liner that contacts the boron-rich film maybe any of the boron nitride or oxide films provided according toembodiments of the invention. The boron nitride liner may also bedeposited according to any of the methods provided herein for formingthe boron nitride films (e.g., by plasma, thermal, or UV-assistedmethods) with the exception that the boron nitride liner is depositedunder conditions sufficient to provide a lower boron concentration inthe liner relative to the boron-rich film. For example, the boron atomicpercent concentration in the liner may be from between 0 and 90%, whilethe boron atomic percent concentration in the boron-rich films may beabout 5% to about 99%. The liner may include oxygen, carbon or silicon.The liner may have a thickness of between about 2 Å and about 500 Å.

The boron-containing films may also be used for hard masks that may besacrificial or left in structures after patterning. For example, theboron-containing films may be boron nitride or boron oxide films thatare hard masks for etching oxide, nitride, silicon, polysilicon, ormetal layers.

The boron-containing films may also be used for back end applications,such as copper barrier layers or as adhesion layers between copper andcopper barrier layers, e.g., by forming CuBN, CuPBN, or CuBCSiN layerstherebetween. The copper barrier layers or adhesion layers may have adielectric constant between 1.1 and 4.0. The copper barrier layers maybe used in conventional damascene structures or structures that includeair gaps that are formed by depositing and then removing a sacrificialmaterial.

Embodiments of a method of depositing a boron nitride film will bedescribed with respect to the flow chart of FIG. 1. As shown in step102, a boron-containing precursor is introduced into a chamber. In step104, a boron-containing film is deposited on a substrate in the chamberfrom the boron-containing precursor. Then, in step 106, theboron-containing film is treated to modify the film composition (e.g.,to increase the nitrogen or oxygen content of the film). Treating theboron-containing film comprises exposing the boron-containing film to anitrogen-containing or oxygen-containing precursor.

Returning to step 102, the chamber into which the boron-containingprecursor is introduced may be any chemical vapor deposition chamber ora plasma enhanced chemical vapor deposition chamber. Examples ofchambers that may be used include the PRODUCER® SE and PRODUCER® GTPECVD chambers, both of which are available from Applied Materials, Inc.of Santa Clara, Calif. The processing conditions provided herein areprovided for a 300 mm PRODUCER® SE chamber with two isolated processingregions, with one substrate per processing region. Thus, the flow ratesexperienced per each substrate processing region and substrate are halfof the flow rates into the chamber.

The substrate on which the boron-containing film is deposited may be asilicon, silicon-containing, or glass substrate. The substrate may be abare substrate or have one or more layers of material deposited thereonand/or features formed therein.

The boron-containing precursor may be diborane (B₂H₆), borazine(B₃N₃H₆), or an alkyl-substituted derivative of borazine. Theboron-containing precursor may be introduced into the chamber at a flowrate between about 5 sccm and about 50 slm, such as between about 10sccm and about 1 slm. Typically, the boron-containing precursor isintroduced into the chamber with nitrogen (N₂), hydrogen (H₂), argon(Ar) or a combination thereof as a dilution gas. The dilution gas may beintroduced into the chamber at a flow rate between about 5 sccm andabout 50 slm, such as between about 1 slm and about 10 slm.

In embodiments in which the boron nitride film that may be formed instep 106 of FIG. 1 is a doped boron nitride film, a compound selectedfrom the group consisting of a silicon-containing compound, acarbon-containing compound, a phosphorous-containing compound, andcombinations thereof may also be introduced into the chamber during thedeposition of the boron-containing film. Alternatively, the compound maybe introduced into the chamber before or after the deposition of theboron-containing film. Example of nitrogen-containing compounds that maybe used include ammonia (NH₃), hydrazine (N₂H₄). Example ofoxygen-containing compounds include oxygen (O₂), nitric oxide (NO),nitrous oxide (N₂O), carbon dioxide (CO₂), and water (H₂O). Examples ofsilicon-containing compounds that may be used include silane,trisilylamine (TSA), trimethylsilane (TMS), and silazanes, such ashexamethylcyclotrisilazane (HMCTZ). Examples of carbon-containingcompounds that may be used include hydrocarbon compounds having thegeneral formula C_(x)H_(y), such as alkanes, alkenes, and alkynes. Anexample of a phosphorous-containing compound that may be used isphosphine (PH₃).

The boron-containing film may be deposited on the substrate in thechamber from the boron-containing precursor in the presence or absenceof a plasma in the chamber.

For deposition of the boron-containing film in the absence of a plasmain the chamber, the temperature of a substrate support in the chambermay be set to between about 100° C. and about 1000° C., e.g., betweenabout 300° C. and about 500° C., and the pressure in the chamber may bebetween about 10 mTorr and about 760 Torr, e.g., between about 2 Torrand about 10 Torr, during the deposition. A combination ofboron-containing, nitrogen-containing, carbon-containing,oxygen-containing and silicon-containing compounds may be introduced inthe chamber at the same time at a flow rate between about 5 sccm andabout 50 slm, such as between 10 sccm and about 1 slm.

For deposition of the boron-containing film in the presence of a plasmain the chamber, the temperature of a substrate support in the chambermay be set to between about 100° C. and about 1000° C., e.g., betweenabout 300° C. and about 500° C., and the pressure in the chamber may bebetween about 10 mTorr and about 760 Torr, e.g., between about 2 Torrand about 10 Torr, during the deposition. The plasma may be provided byRF power delivered to a showerhead electrode and/or a substrate supportelectrode of the chamber. The RF power may be provided at a power levelbetween about 2 W and about 5000 W, such as between about 30 W and about1000 W, at a single low frequency of between about 100 kHz up to about 1MHz, e.g., about 300 kHz to about 400 kHz, or at a power level betweenabout 2 W and about 5000 W, such as between about 30 W and about 1000 W,at a single high frequency of greater than about 1 MHz, such as greaterthan about 1 MHz up to about 60 MHz, e.g., 13.6 MHz. Alternatively, theRF power may be provided at a mixed frequency including a firstfrequency between about 100 kHz up to about 1 MHz, e.g., about 300 kHzto about 400 kHz at a power level between about 2 W and about 5000 W,such as between about 30 W and about 1000 W, and a second frequency ofgreater than about 1 MHz, such as greater than about 1 MHz up to about60 MHz, e.g., 13.6 MHz, at a power level between about 2 W and about5000 W, such as between about 30 W and about 1000 W.

Returning to step 106, after the boron-containing film is deposited, theboron-containing film is treated to modify its composition byincorporating nitrogen or oxygen into the film and form a boron nitrideor boron oxide film. The boron nitride or boron oxide film may have athickness of between about 2 Å and about 5000 Å. The treatment isselected from the group consisting of a plasma process, an ultraviolet(UV) cure process, a thermal anneal process, and combinations thereof,and comprises exposing the boron-containing film to anitrogen-containing precursor to incorporate nitrogen into the film andform the boron nitride film. The nitrogen-containing precursor may benitrogen gas (N₂), ammonia (NH₃), or hydrazine (N₂H₄), for example. Thenitrogen-containing precursor may be diluted with a dilution gas such asargon, helium, hydrogen, or xenon. Exposing the boron-containing film toa oxygen-containing precursor allows incorporation of oxygen in the filmand formation of a boron oxide film. The oxygen-containing precursor maybe oxygen gas (O₂), nitrous oxide (N₂O) or carbon dioxide (CO₂).

In embodiments in which the treatment comprises a plasma process, theplasma process may be performed in the same chamber in which theboron-containing film was deposited or a different chamber. The plasmamay be provided by RF power delivered to a showerhead electrode and/or asubstrate support electrode of the chamber. The RF power may be providedat a power level between about 2 W and about 5000 W, such as betweenabout 30 W and about 1000 W, at a single low frequency of between about100 kHz up to about 1 MHz, e.g., about 300 kHz to about 400 kHz, or at apower level between about 2 W and about 5000 W, such as between about 30W and about 1000 W, at a single high frequency of greater than about 1MHz, such as greater than about 1 MHz up to about 60 MHz, e.g., 13.6MHz. Alternatively, the RF power may be provided at a mixed frequencyincluding a first frequency between about 100 kHz up to about 1 MHz,e.g., about 300 kHz to about 400 kHz at a power level between about 2 Wand about 5000 W, such as between about 30 W and about 1000 W, and asecond frequency of greater than about 1 MHz, such as greater than about1 MHz up to about 60 MHz, e.g., 13.6 MHz, at a power level between about2 W and about 5000 W, such as between about 30 W and about 1000 W. Thenitrogen-containing precursor may be introduced into the chamber at aflow rate of between about 5 sccm and about 50 slm, such as betweenabout 100 sccm and about 500 sccm, during the treatment. Thenitrogen-containing precursor may be flowed into the chamber for aperiod of time, such as between about 1 second and about 2 hours, suchas between about 1 second and about 60 seconds. The chamber pressure maybe between about 10 mTorr and about 760 Torr, and the temperature of asubstrate support in the chamber may be between about 20° C. and about1000° C. during the treatment. increased high frequency RF power,increased NH₃ flow rates, and longer treatment times of the plasmaprocess can be used to lower the refractive index of the resulting filmsand increase the dielectric properties of the films.

In embodiments in which the treatment comprises a UV cure process, theUV cure process may be performed in the same chamber as the depositionchamber or in a chamber which is part of an integrated tool thatincludes the deposition chamber in which the boron-containing film wasdeposited. For example, the UV cure process may be performed in aNANOCURE™ chamber that is part of a PRODUCER® platform that includes aPECVD chamber in which the boron-containing film is deposited.

Exemplary UV cure process conditions that may be used include a chamberpressure of between about 10 mTorr and about 760 Torr and a substratesupport temperature of between about 20° C. and about 1000° C. Thenitrogen-containing precursor may be introduced into the chamber at aflow rate of between about 5 sccm and about 50 sccm during thetreatment. The nitrogen-containing precursor may be flowed into thechamber for a period of time such as between about 1 second and about 2hours, such as between about 1 second and about 10 minutes. The UVradiation may be provided by any UV source, such as mercury microwavearc lamps, pulsed xenon flash lamps, or high-efficiency UV lightemitting diode arrays. The UV radiation may have a wavelength of betweenabout 170 nm and about 400 nm, for example. The treatment may compriseexposing the boron-containing film to between about 1 Watt/cm² and about1000 Watts/cm² of ultraviolet radiation, and the ultraviolet radiationmay provide a photon energy (electronVolts) between about 0.5 eV andabout 10 eV, such as between about 1 eV and about 6 eV.

Typically, the UV cure process removes hydrogen from the film, which isdesirable as hydrogen can diffuse through the film and intosemiconducting regions of the substrate and degrade reliability of adevice formed on the substrate. The UV cure process also typicallydensifies the film and increases the tensile stress of the film togreater than about 2.0 GPa.

In embodiments in which the treatment comprises a thermal process, thethermal process may be performed in the same chamber in which theboron-containing film was deposited or a different chamber. Thenitrogen-containing precursor may be introduced into the chamber at aflow rate of between about 5 sccm and about 50 slm, such as betweenabout 10 sccm and about 1 slm, during the treatment. Thenitrogen-containing precursor may be flowed into the chamber for aperiod of time such as between about 1 second and about 10 hours, suchas between 10 seconds and about 20 minutes. The chamber pressure may bebetween about 10 mTorr and about 760 Torr, and the temperature of asubstrate support in the chamber may be between about 20° C. and about1000° C. during the treatment.

Further embodiments include treating the boron-containing film with twoor more of the treatments described above, i.e., UV cure processes,plasma processes, and thermal processes. For example, theboron-containing film may be treated with a UV cure process and then aplasma process.

For applications in which high step coverage and a minimal patternloading effect are required, such as when the boron nitride film isdeposited as a spacer layer over a gate stack, multiple cycles of steps102, 104, and 106 may be performed. In other words, after step 106, theboron-containing precursor is introduced into the chamber, an additionalamount of the boron-containing film is deposited on the substrate, andthe boron-containing film is treated with a process selected from thegroup consisting of a plasma process, a UV cure process, a thermalanneal process, and combinations thereof, wherein the treating comprisesexposing the boron-containing film to a nitrogen-containing precursor toincorporate nitrogen or to an oxygen-containing precursor to incorporateoxygen into the film and form a boron nitride or boron oxide filmrespectively. Steps 102, 104, and 106 may be repeated until a desiredthickness of the boron nitride film is obtained. By forming thinsub-layers of the final boron nitride or boron oxide film, such as about2 Å to about 5000 Å layers, for example, about 2 Å to about 1000 Å,e.g., about 20 Å layers, in each cycle, the step coverage and patternloading effect can be improved relative to processes in which the filmis deposited to the final desired thickness in one cycle. For example, astep coverage of greater than 95% and a pattern loading effect of lessthan 5% were obtained when a boron nitride film was formed under thefollowing conditions: depositing a boron-containing film at a depositionrate of 20 Å per cycle using 400 sccm of diborane and 2000 sccm ofnitrogen at a chamber pressure of 6 Torr and a spacing of 480 mils for 5seconds/cycle; and treating the boron-containing film with a plasmaprocess to incorporate nitrogen into the film and form a boron nitridefilm, wherein the plasma process comprises using 100 sccm of ammonia and2000 sccm of nitrogen for 10 seconds/cycle with 300 W of RF power at13.6 MHz. The boron nitride film had a dielectric constant of 4.7. Therefractive index at 500 Å was 1.810, and the density was 2.4 g/cm³. Theleakage current at 1 MV was 3e⁻⁰⁹ amps/cm², and the leakage current at 2MV was 4e⁻⁰⁸ amps/cm². The breakdown voltage (Vbd) was 5 MV/cm.

In further examples, boron nitride films for use as stress nitridelayers were deposited under the following conditions: depositing aboron-containing film using a 25 or 50 sccm flow of diborane at achamber pressure of 6 Torr and a spacing of 480 mils at a substratesupport temperature of 400° C. for 10 seconds and then treating theboron-containing film with a plasma to incorporate nitrogen into thefilm and form a boron nitride film, wherein the plasma process comprisesusing 100 sccm of ammonia and 2000 sccm of nitrogen for 10 seconds/cyclewith 100 W of RF power at 13.6 MHz. The deposition of theboron-containing film and the plasma treatment were repeated for 10cycles. The film deposited using 25 sccm of diborane had a sidewall/topstep coverage of 100% and a bottom/top step coverage of 98%. The filmdeposited using 50 sccm of diborane had a sidewall/top step coverage of99% and a bottom/top step coverage of 100%. The films were also shown tobe thermally stable after 30 minutes of annealing at 900° C. Thus, thefilms provided herein exhibit desirable high densities and electricalproperties.

FIG. 2 is a FTIR that shows the effect of different N₂ flow rates duringtreatment of boron-containing films with N₂ on the composition of theresulting boron nitride layers. FIG. 2 illustrates that the compositionof the boron nitride layer can be modulated by tuning the flow rate ofthe nitrogen-containing precursor during the treatment of theboron-containing film with nitrogen. It was also found that using alower flow rate of diborane provides boron nitride films with a highernitrogen content and a lower refractive index.

FIG. 3 is a FTIR that shows the effect of different substrate supporttemperatures during the deposition of boron-containing films on thecomposition of the subsequently formed boron nitride layers. FIG. 3illustrates that the composition of the boron nitride layer can also bemodulated by tuning the substrate support temperature.

In addition to film composition, other properties of the boron nitridefilms, such as refractive index (RI) and step coverage, can be tailoredby introducing other precursors into the chamber during the introductionof the boron-containing precursor in step 102. Films deposited usingB₂H₆, B₂H₆+NH₃, B₂H₆+SiH₄, and B₂H₆+NH₃+SiH₄ during step 102 werecompared. The B₂H₆+SiH₄ films had the highest refractive index. Filmsthat were deposited using an additional precursor rather than B₂H₆ alonehad improved uniformity. The B₂H₆+NH₃+SiH₄ films had the best stepcoverage. For example, a bottom/top step coverage of 91%, a sidewall/topstep coverage of 91%, a top PLE of 0%, a sidewall PLE of 7%, and abottom PLE of 5% were obtained using the following conditions: 400 sccmB₂H₆ (5% in N₂), 40 sccm SiH₄, 200 sccm NH₃, 4000 sccm N₂ for 15 secondsfollowed by a nitrogen plasma treatment comprising 600 W RF power at13.6 MHz, 100 sccm NH₃, and 6000 sccm N₂ for 15 seconds.

While a substrate is exposed to the boron-containing precursor and thenitrogen-containing precursor sequentially in the embodiments describedwith respect to FIG. 1, in alternative embodiments, a substrate isexposed to the boron-containing precursor and the nitrogen-containingprecursor (and/or an oxygen-containing) precursor simultaneously. Insuch embodiments, the boron-containing precursor and thenitrogen-containing or oxygen-containing precursor are introduced into achamber and then reacted to chemically vapor deposit a boron nitride orboron oxide film on a substrate in the chamber. Optionally, asilicon-containing compound, a carbon-containing compound, aphosphorous-containing compound, or combination thereof may also beintroduced into the chamber at the same time to deposit a doped boronnitride film. The reaction of the boron-containing precursor, thenitrogen-containing or oxygen-containing precursor, and the optionalother compounds may be performed in the presence or absence of a plasmain the chamber.

By introducing the precursors simultaneously, a higher deposition ratemay be achieved. Thus, embodiments in which the substrate is exposed tothe boron-containing precursor and the nitrogen-containing precursorsimultaneously provide desirable methods of forming boron nitride filmsfor applications which do not have high step coverage and patternloading requirements, such as for hard mask layers.

The boron-containing precursor and the nitrogen-containing precursor maybe any of the precursors described above with respect to the embodimentsof FIG. 1. Similarly, the chamber and substrate may be any of thechambers and substrates, respectively, described above with respect tothe embodiments of FIG. 1.

The boron-containing precursor may be introduced into the chamber withnitrogen (N₂), hydrogen (H₂), argon (Ar) or a combination thereof as adilution gas. The boron-containing precursor may be introduced into thechamber at a flow rate between about 5 sccm and about 50 slm, such asbetween about 10 sccm and about 1 slm. The nitrogen-containing precursormay be introduced into the chamber at a flow rate between about 5 sccmand about 50 slm, such as between about 10 sccm and about 1 slm. Thedilution gas may be introduced into the chamber at a flow rate betweenabout 5 sccm and about 50 slm, such as between about 1 slm and about 10slm.

In embodiments in which the boron-containing precursor and thenitrogen-containing precursor are reacted in the presence of a plasma, achamber pressure of between about 10 mTorr and about 760 Torr, e.g.,between about 2 Torr and about 10 Torr, and a substrate supporttemperature of between about 100° C. and about 1000° C., e.g., betweenabout 300° C. and about 500° C., may be used during the deposition. Thespacing between a showerhead of the chamber and the substrate supportmay be between about 100 mils and about 10000 mils. The plasma may beprovided by RF power delivered to a showerhead electrode and/or asubstrate support electrode of the chamber. The RF power may be providedat a power level between about 2 W and about 5000 W, such as betweenabout 30 W and about 1000 W, at a single low frequency of between about100 kHz up to about 1 MHz, e.g., about 300 kHz to about 400 kHz, or at apower level between about 2 W and about 5000 W, such as between about 30W and about 1000 W, at a single high frequency of greater than about 1MHz, such as greater than about 1 MHz up to about 60 MHz, e.g., 13.6MHz. Alternatively, the RF power may be provided at a mixed frequencyincluding a first frequency between about 100 kHz up to about 1 MHz,e.g., about 300 kHz to about 400 kHz at a power level between about 2 Wand about 5000 W, such as between about 30 W and about 1000 W, and asecond frequency of greater than about 1 MHz, such as greater than about1 MHz up to about 60 MHz, e.g., 13.6 MHz, at a power level between about2 W and about 5000 W, such as between about 30 W and about 1000 W.

The embodiments in which the boron-containing precursor and thenitrogen-containing precursor are reacted in the presence of a plasmaprovide boron nitride films that have properties that are desirable forhard mask applications. For example, wet etch rate ratios (100:1 HF) of0.03 and 0.3 for thermal oxide and thermal nitride, respectively, havebeen obtained. Argon may be added to the precursor mixture to lower thedielectric constant of the films and increase the breakdown voltage.These films also have properties that are desirable for back-end of lineapplications such as copper barrier layers. In an exemplary embodiment,diborane diluted with nitrogen and ammonia are introduced into a chamberand reacted in the presence of a plasma provided by RF power to deposita boron nitride film on a substrate in the chamber. The diborane wasintroduced into the chamber at a flow rate of about 3000 sccm, 5% in N₂,and the ammonia was introduced into the chamber at a flow rate of about150 sccm. The RF power was provided at about 300 W at a frequency of13.6 MHz. The chamber pressure was about 6 Torr, and the spacing wasabout 480 mils. Boron nitride films with low wet etch rates, highdeposition rates, and desirable, low dielectric constants were obtained.

In embodiments in which the boron-containing precursor and thenitrogen-containing, oxygen-containing, carbon-containing and/orsilicon-containing precursor are reacted in the absence of a plasma, achamber pressure of between about 10 mTorr and about 760 Torr and asubstrate support temperature of between about 100° C. and about 1000°C. may be used during the deposition. The spacing between a showerheadof the chamber and the substrate support may be between about 50 milsand about 5000 mils.

In a further embodiment in which the boron-containing precursor and thenitrogen-containing precursor are introduced simultaneously, asilicon-containing precursor may also be introduced into the chamberwith the boron-containing precursor and the nitrogen-containingprecursor to form a SiBN film for spacer applications. The SiBN film mayhave a dielectric constant of less than 5.5, a breakdown voltage ofgreater than 6 MV/cm, and a leakage current of less than 1e⁻⁹ amps/cm²at 2 MV. Exemplary processing conditions for depositing a SiBN filminclude: 60 sccm SiH₄, 600 sccm NH₃, 1000 sccm N₂, 100-1000 sccm B₂H₆,100 W RF power at 13.6 MHz, a chamber pressure of 6 Torr, and a spacingof 480 mils. Optionally, the SiBN film may be UV cured for 10 minutes at400° C.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method of forming a boron nitride film or boron oxide film,comprising: introducing a boron-containing precursor into a chamber;depositing a boron-containing film on a substrate in the chamber fromthe boron-containing precursor; treating the boron-containing film toincrease the nitrogen or oxygen content in the film and form a boronnitride film or boron oxide film; and repeating the introducing,depositing, and treating until a desired thickness of the boron nitridefilm or boron oxide film is obtained.
 2. The method of claim 1, whereinthe boron oxide film and the boron nitride film are boron-doped oxidefilms and boron-doped nitride films respectively.
 3. The method of claim2, wherein the boron nitride film is a spacer or stress nitride layerhaving a stress between 10 GPa compressive and 10 GPa tensile.
 4. Themethod of claim 2, further comprising using the boron nitride film orthe boron oxide film to dope an underlying layer or an above layer withboron.
 5. The method of claim 2, wherein the boron nitride film or theboron oxide film is used as a boron diffusion barrier below or above aboron-rich film, and the boron nitride film or the boron oxide film hasa lower boron atomic percent concentration than the boron-rich film. 6.The method of claim 2, wherein the boron nitride film or the boron oxidefilm is a copper barrier layer.
 7. The method of claim 2, wherein theboron oxide film or the boron nitride film is an adhesion layer betweencopper and a copper barrier layer.
 8. The method of claim 2, wherein theboron nitride film has a dielectric constant between 1.1 and
 10. 9. Themethod of claim 1, wherein the boron-containing film is deposited in thepresence or absence of a plasma.
 10. The method of claim 1, furthercomprising introducing a nitrogen-containing compound, anoxygen-containing compound, a silicon-containing compound, acarbon-containing compound, a phosphorous-containing compound, or acombination thereof into the chamber during the deposition of theboron-containing film, and the boron-containing film is a doped boronnitride film or a doped boron oxide film.
 11. The method of claim 10,wherein the silicon-containing compound is selected from the groupconsisting of silane, trisilylamine (TSA), trimethylsilane (TMS), andsilazanes.
 12. The method of claim 10, wherein the oxygen-containingcompound is selected from the group consisting of oxygen gas, nitricoxide (NO), nitrous oxide (N₂O), carbon dioxide (CO₂), and water (H₂O).13. The method of claim 10, wherein the carbon-containing compoundcomprises a hydrocarbon compound having the general formula C_(x)H_(y).14. The method of claim 10, wherein a phosphorous-containing compound isintroduced into the chamber during the deposition of theboron-containing film, and the phosphorus-containing compound isphosphine.
 15. The method of claim 1, wherein the boron-containingprecursor is selected from the group consisting of diborane, borazine,and alkyl-substituted derivatives of borazine.
 16. The method of claim1, wherein the nitrogen-containing precursor is selected from the groupconsisting of ammonia, nitrogen gas, and hydrazine.
 17. The method ofclaim 1, wherein the treating the boron-containing film furthercomprises exposing the boron-containing film to a plasma process, a UVcure process, a thermal anneal process, or a combination thereof. 18.The method of claim 1, wherein the treating comprises exposing theboron-containing film to a nitrogen-containing or oxygen-containingprecursor.
 19. The method of claim 1, wherein the thickness of the filmobtained in the depositing the boron-containing film is between 2 Å and1000 Å.
 20. A method of forming a boron nitride film or a boron oxidefilm, comprising: introducing a boron-containing precursor and anitrogen-containing precursor or an oxygen-containing precursor into achamber; and reacting the boron-containing precursor and thenitrogen-containing precursor or oxygen-containing precursor tochemically vapor deposit a boron nitride or boron oxide film on asubstrate in the chamber.
 21. The method of claim 20, wherein theboron-containing precursor and the nitrogen-containing precursor arereacted in the presence or absence of a plasma in the chamber.
 22. Themethod of claim 20, further comprising introducing a compound selectedfrom the group consisting of a silicon-containing compound, acarbon-containing compound, a phosphorous-containing compound, andcombinations thereof into the chamber and reacting the compound with theboron-containing precursor and the nitrogen-containing precursor oroxygen-containing precursor, wherein the deposited boron nitride film orboron oxide film is a doped boron nitride film or doped boron-oxide filmrespectively.
 23. The method of claim 20, wherein the boron nitride filmis a stress nitride layer, a spacer layer or a boron source layer fordoping an underlying layer and has a dielectric constant between 1.1 and6.0.
 24. The method of claim 20, wherein the boron nitride film or theboron oxide film is a hard mask layer for etching an oxide, nitride,silicon, polysilicon or metal layer,
 25. The method of claim 20, whereinthe boron nitride film or the boron oxide film is a copper barrier layerhaving a low dielectric constant between 1.1 and 4.0.